Mining is not about allocating the issuance of new coins. The fact that they are tied together in Bitcoin is a temporary coincidence. Mining is about solving the problem of distributed consensus - how do a bunch of independent nodes spread all over the planet agree on a precise ordering of transactions when every node must operate with an incomplete view of the network and anybody might be trying to cheat?
This problem has nothing to do with elitism or notions of fairness or populism. Overlaying those agendas into the solution is a great way to not solve the problem.
As nodes on the network continually work to establish a consistent of narrative of what has happened in the netwowk based on their own incomplete knowledge, there will be times where two nodes disagree. Mining is nothing more than a signalling mechanism which provides an objective basis for choosing which version of history to treat as correct, whenever a conflict occurs such that more than one alternative version exist.
The design criteria for what makes a good mining algorithm comes from signalling theory:
They could both gain if they could honestly share this information.
However, their interests do not coincide entirely, and so each has an incentive to deceive the other.
How can honest communication be ensured?
Economists and biologists independently proposed that the costs associated with producing signals can provide a solution to this problem. Loosely paraphrased, the solution typically takes the following form.
If telling the truth is cheap enough and telling a lie is costly enough, it may be worthwhile to communicate honestly but not to lie.
The signal sent by proof of work is the amount of opportunity cost the miner has paid in order to produce the block. The fact that mining calculations are completely useless outside the signalling system itself is what makes lies more expensive than telling the truth, thus satisfying the conditions for honest signalling. The opportunity cost the miner pays to produce a block only represents a profitable trade for the miner if the network accepts their block. So when it comes to a node in the network choosing between two valid blocks, choosing to accept the block with the higher PoW means choosing the block which produced by the miner who has the most at stake in terms of opportunity cost paid.
Note that if the miner has to use specialized hardware for which there is no possible use other than mining, the signal is even better than performing otherwise-useless calculations on general purpose hardware. Higher opportunity costs = more reliable signal.
Proof of work is a proof of stake system, the only one that actually works.
PoS coins use the number of coins held as the basis for their signalling system. Since coins have an exchange rate, they obviously do not fulfill the criteria of having no value, either practical or intellectual. Thus PoS is not an viable mechanism for honest signalling.
Latter emphasis mine.